1. Technical Field
The invention relates to an adhesive tape, and, more particularly, to an adhesive tape for electronic components that can be used for bonding electronic components such as leads, heat sinks, semiconductor chips, die pads, and the like, excellent in taping capability and electric reliability.
2. Description of the Prior Art
Generally, typical adhesive tapes used for semiconductor devices include adhesive tapes for bonding lead frames, those for attaching heat sinks, TAB (Tape Automated Bonding) tapes, LOC (Lead On Chip) tapes, and the like. The adhesive tapes for bonding lead frames is used for fixing the lead of a lead frame to improve productivity and yields of the lead frame itself and in the overall semiconductor assembly process. A lead frame manufacturer applies the adhesive tape onto a lead frame, which is in turn delivered to a semiconductor assembling company, to equip semiconductor chips on the frame which is subject to wire bonding, etc. and then to seal the frame with an epoxy molding compound. Therefore the adhesive tape is contained in a semiconductor apparatus package.
The tapes such as the adhesive tape for attaching heat sinks are also contained in a semiconductor package, like the adhesive tapes for bonding lead frames.
Therefore, the adhesive tapes for electronic components must have general reliability and workability in taping for semiconductors, and sufficient physical properties that allow the tapes to resist severe conditions such as high temperature, humidity, voltage, etc. applied from the outside during the assembling process of a semiconductor device until they are used as final products after the assembling process, as well as excellent adhesiveness.
Typical adhesive tapes for electronic components used as such are made by applying only the synthetic rubbery resin of polyacrylonitrile resin, polyacrylate resin, resole phenol resin, or acrylonitrile-butadiene copolymer, etc. onto a heat-resistant film such as a polyimide film, or by applying an adhesive made on the film by modifying the resins to another resin or mixing the resins, and then being converted to B step through coating and drying the applied adhesive. Such a tape, however, introduces excessive bleeding of the adhesive in taping because its hardness is too low, which excessive bleeding causes the adhesive to stain taping devices or to bleed on unnecessary portions, which in turn results in defective semiconductor devices.
With the current micro- and highly-integrated package architecture resulting from a thin body and fine pitch structure of a semiconductor device, stringent requirements for organic materials such as adhesive tapes and the like used for the devices tend to be applied to their electric, chemical and physical properties. Accordingly, there has been a need for developing adhesive tape compositions for electronic components excellent in adhesiveness, workability and the like together with sufficient electric reliability and durability.
To solve the aforementioned problems, the applicant TORAY SAEHAN disclosed a document, titled “Heat-resistant adhesive tape for electronic components”, of the Korea Patent Application No. 2002-0043621 (published Korea Pat. No. 2004-0009616) and a document, titled “Adhesive tape compositions for electric components” of the Korea Patent Application No. 2004-84712. With the compositions disclosed in the above patent specifications, many problems in adhesiveness, electric reliability and the like were much improved as compared to conventional adhesive tapes and the improved adhesive tape has been widely used in the relevant field currently.
As electronic and semiconductor components continue to develop with a micro-, thin- and highly-integrated structure in the electronic industry, there has been a need for continuous development of adhesive tapes for electronic components to catch up with the trend. The invention was designed during the research to improve the problems of conventional adhesive tapes for electronic components.